Gas turbine engines are generally adapted to be used with a single type of jet fuel, for example JP4 jet fuel. As such, use of a different fuel, for example ethanol, in these engines can be detrimental to the engines' performances, as the fuel flow in the engine is usually controlled through a series of fuel schedules established for a specific type of fuel and as such not adapted for other types of fuel of mixtures thereof.
With the rise of fuel costs, some areas of the world may choose to use Ethanol or mixtures of Ethanol in Jet fuel, accepting a reduced flight range for the cost savings. However, refuelling with a fuel that may be different from the fuel already contained in the tank can cause the precise equivalent content of the fuel tanks to be unknown. A pilot who is confused as to the exact type of fuel contained in the fuel tanks can be mistaken upon calculation of the range of the aircraft. This can be hazardous, especially in cases where the range is overestimated.
Accordingly, there is a need to provide an improved fuel control system for a gas turbine engine.